I suspect the root cause of your problem, likely to be seen
on Linux/Perl 5.8.0 only, is that the STDOUT file handle is UTF-8
due to your LOCALE settings. I was able to duplicate your problem
in that environment. It can be fixed by setting the LANG environment
variable, as shown below:

The root cause of this nuisance is described, as follows,
in the perl 5.8.1 perldelta.

UTF-8 On Filehandles No Longer Activated By Locale

In Perl 5.8.0 all filehandles, including the standard filehandles,
were implicitly set to be in Unicode UTF-8 if the locale settings
indicated the use of UTF-8. This feature caused too many problems,
so the feature was turned off and redesigned: see Core Enhancements.

UTF-8 no longer default under UTF-8 locales

In Perl 5.8.0 many Unicode features were introduced. One of them was
found to be of more nuisance than benefit: the automagic (and silent)
``UTF-8-ification'' of filehandles, including the standard filehandles,
if the user's locale settings indicated use of UTF-8.

For example, if you had en_US.UTF-8 as your locale, your STDIN and STDOUT
were automatically ``UTF-8'', in other words an implicit binmode(..., ``:utf8'')
was made. This meant that trying to print, say, chr(0xff), ended up printing
the bytes 0xc3 0xbf. Hardly what you had in mind unless you were aware of this
feature of Perl 5.8.0. The problem is that the vast majority of people weren't:
for example in RedHat releases 8 and 9 the default locale setting is UTF-8,
so all RedHat users got UTF-8 filehandles, whether they wanted it or not.
The pain was intensified by the Unicode implementation of Perl 5.8.0 (still)
having nasty bugs, especially related to the use of s/// and tr///.
(Bugs that have been fixed in 5.8.1)

Therefore a decision was made to backtrack the feature and change it from
implicit silent default to explicit conscious option. The new Perl command
line option -C and its counterpart environment variable PERL_UNICODE can
now be used to control how Perl and Unicode interact at interfaces like
I/O and for example the command line arguments. See -C in the perlrun
manpage and PERL_UNICODE in the perlrun manpage for more information.